1. Field of the Invention
The present invention relates to a robot, and more particularly to a robot that can be used in special environments including space, vacuums, clean rooms, and liquids where dust and lubrication are matters of important concern.
2. Description of the Prior Art
In special environments including space, vacuums, clean rooms, and liquids, dust particles produced by contact elements of actuators tend to cause problems, and bearings of such actuators need to be lubricated. One example of such a special environment is in the semiconductor manufacturing industries. Specifically, efforts to achieve higher levels of large scale integration in semiconductor devices result in demands for higher dust control standards in semiconductor manufacturing environments and equipment. One attempt to meet such demands is to make the semiconductor manufacturing processes as automatic as possible using robots. The robots thus used in the semiconductor manufacturing systems produce dust particles and require maintenance of lubricated parts.
More specifically, as is well known in the art, the semiconductor manufacturing processes employ clean rooms for maintaining high levels of dust, temperature, and humidity control. Robots for use in such clean rooms should meet certain requirements with regard to dust control and operation reliability among others. For example, the robots should be equipped with a low-dust or dust-free mechanism for reducing or eliminating elements which would otherwise produce an undesirable amount of dust particles, or with a dust-prevention mechanism for preventing dust particles from flowing out of the robots and from being scattered around. The robots should also be highly reliable so that they will be maintenance-free.
Specific arrangements that are effective to meet the above requirements are as follows. A negative pressure is developed in the robot to cause air to flow from outside into the robot at all times for thereby preventing dust particles from flowing through any openings of the robot. The inner space of the robot is completely separated from the outer environment by magnetic fluid seals to prevent dust particles from being scattered out of the robot. Brushless AC servomotors are employed as actuators in the robot because the brushless AC servomotors generate less dust than DC servomotors and are maintenance-free.